Edger saw guide plug

ABSTRACT

A vibration damping means for circular saws in which guide plug pairs straddle saw at peripherally spaced positions in plug holder. Two plug pairs are spaced diametrically opposite to each other at leading and following positions, a third pair being at about 70* from leading edge pair towards following pair. Plugs are held in holder by pinch bolt means, or are held by expanding plugs radially by pipe threaded stud screwed into pipe threaded bore in plug, the plug having radial slot for expansion.

United States Patent 11 1 McMillan Nov. 20, 1973 [54] EDGER SAW GUIDE PLUG 668,343 2/1901 Roe 83/829 [76] Inventor: James R. McMillan Box 17, Lone 233,563 10/1880 Sherman 83/829 h C l b' C Butte Brms o um la anada Primary Examiner-Donald R. Schran Filedl 1971 Attorney-Brian J. Wood [21] Appl. No.: 140,446

[57] ABSTRACT [30] Foreign Application Priority Data A vibration damping means for circular saws in which May 6, 1970 Great Britain 21,703 70 suido P Pairs straddle Saw at P p y Spaced positions in plug holder. Two plug pairs are spaced di- 521 US. Cl 83/827, 83/829, 83/821 omoo'ioolly opposite to each other at leading and 51 Int. Cl B27b 5/28, B27b 7/04 lowing positions, a third P being at about from [58] Field of Search 143/160; 83/821, loading edge P towards following P Pluss are 83/327, 829 5 4253, 254 held in holder by pinch bolt means, or are held by expanding plugs radially by pipe threaded stud screwed 5 References Cited into pipe threaded bore in plug, the plug having radial UNITED STATES PATENTS 10 Claims, 6 Drawing Figures PAIENTEDNUV 20 I975 3.772.956

' sum 1 m 4 &

EDGER SAW GUIDE PLUG BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to improvement is sawmill machinery, particularly to improvement in means of securing guide plug pairs to damp vibration of circular saws and in their positioning.

Nomenclature Terminology as below listed Flitch A timber with parallel sawn top and bottom surfaces and waney edges.

Cant A sawn timber produced for instance by removing the waney edges from a flitch, the cant being re-sawn to produce dimensioned stock.

Gang saw A series of co-axial circular saws on a common drive shaft.

2. Prior Art The use of plug pairs for damping vibrations in circular saw is well known. The present invention teaches an improved plug construction with simplified securing means so as to attain nice adjustment of clearance of the plugs from the saw, and permit desired disposition of the plug pairs by means of a structure simpler than that of the prior art known to the present inventor.

Vibration phenomena in circular saws are complex,

most research has been and is being conducted directed to number and disposition of plug pairs for optimum damping under particular conditions. Gang saws as contemplated herein are expected to produce dimensioned lumber to tolerance as close as twenty-five thousandths of an inch, thus the importance of this problem is seen, and related thereto, is a problem of securing the plugs, which are commonly of lignum vitae or of known composition commonly used for such purposes, rigidly and at the same time providing means of adjustment of clearance to a close tolerance.

SUMMARY OF THE INVENTION The invention provides guide plug pairs secured in fixed holders at a small clearance from opposite surfaces of the saw, so as to provide damping.

Alternative means of adjusting the small clearance, normally about five one thousandths of an inch, are taught.

The inventor has found that diametrically opposite plug pairs supplemented by a third plug pair some 70 from a leading plug pair, particularly in combination with means above, gives improved damping and, consequently, improved dimensional control.

While the present invention contemplates gang saws, it can be used to advantage in damping vibration of a single circular saw.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of an edger having two saws, FIG. 2 is a simplified fragmented side elevation of an edger saw assembly viewed along an axis of an arbor,

and in structure other than that particularly described and illustrated.

DETAIL DISCLOSURE Saw Kerf With saws spaced at a particular distance apart, stock produced by the saws is narrower than the particular distance by an amount equal to saw kerf loss, throughout this disclosure, to facilitate description, loss of dimension due to saw kerf is disregarded.

FIGS. 1 and 2 An edger generally 10, having a housing 10.1 has two circular saw blades 1 l and 12 mounted for rotation on an arbor 13. A blade guide assembly 15 is mounted above the blades, and has oppositely disposed blade guide holders, l6 and 17 secured to supports 18 and 19 which extend from the housing 10.1 as shown. Two further support holders 20 and 21 are provided for use if required, but as shown are not carrying guide holders. The holders are generally semi-circular as shown, and of radial depth to extend nearly to the throats of the teeth. Collars on either side of each blade secure the blade to the arbor, one collar 14 only being shown in FIG. 1. The collar 14 has an outer surface 14.1 (FIG. 1 only). Steadies 22 and 23 extend outwards from the housing 10.1 and support the blade guide holders 16 and 17 as shown. A guide plug pair 24 is provided secured in an opening at a lower end 16.1 of the guide holder 16 and a guide plug pair 25 is provided at opposite lower ends of the holders. In FIG. 1 one guide plug only of each guide plug pair is seen. The holder 17 has similar guide plug pairs (not shown) and lumber, for instance a flitch, passing through the edger moves in a direction shown by an arrow 27, passing over conveyor rolls 28. Feed rolls 30 pass the flitch through the saw blades producing a cant from the flitch. The feed rolls rotate in a direction shown by arrows 31 (FIG. 2 only). FIG. 3

The blade 12 is mounted between the guide plug pair 25, the plug pair 25 including two plugs 33 and 34 spaced oppositely to each other on either side of the saw blade 12. The blade 12 has surfaces 12.1 and 12.2 as shown and the plugs 33 and 34 have inner faces 35 and 36 respectively, which faces are spaced from the surfaces 12.1 and 12.2 of the blade by a small controlled clearance, the order of five thousandths of an inch. This controlled clearance is adjustable by pinch bolt means 37 and 38 best seen in FIG. 2.

To change a position of the blade 12 on the arbor, the blade guide holder 16 is moved longitudinally along the the support 18, one guide plug of each guide plug pair 24 and 25 contacting the blade 12 and moving it and with it the collar 14, to a different station on the arbor.

ALTERNATIVE PLUG STRUCTURE In FIG. 2, plug pairs 24 and 25 are secured and adjusted by pinch bolt means 37 and 38. Alternative securing and adjustment means are shown in FIGS. 4, 5, and 6 which also show an additional plug pair. The pinch bolt means not being required, certain advantages result.

FIGS. 4, 5, and 6 Referring to FIGS. 4 and 5, a generally semi-circular guide holder 200 is U-shaped in section having opposite sides 200.1 and 200.2 spaced to accommodate the saw 12 as seen in FIG. 5. The holder has a circular wise (i.e. towards the followingopening) from a lead; ing opening 201 .1. The 70 angle is not critical within plus or minus about 5. A following opening 201.2 is

diametrically opposite the leading opening, and each of the openings extends through both the sides 200.1, 200.2, of the guide. Guide plug pairs ar e ins erted in the openings, side walls of the open in gs bei ig cylindrical and the guide plugs having complementary cylindrical side walls. A guide plug 202 is shown in elevation in FIG. 6and in section in FIG. 5, the plug having central bore 203, tapped to provide a pipe thread 203.1. A radial slot 204 extends to the central bore, and can extend as shown at 205 to a total length of about three quarters of a diameter. The bore 203 accepts a pipe threaded stud 206 so that when the stud is inserted in the opening 201, and screwed into the bore, the guide plug expands against side walls of the opening 201 so securing it in position. Adjustment is made as before to effect the required position the stud having a hex opening 207 to accept an Allen wrench used in tightening.

The openings of the holder 200 are concentric about the saw axis, and are positioned so that radial peripheries of the plgus, as 209 FIG. 5 are adjacent to throats 211 of teeth of the saw, the peripheries are or can be closer than shown in FIG. 2.

As has been pointed out, vibrations in a circular saw are complex, it is found that better damping can be effected by means including the plug pairs at 70 from the leading plug with clearance adjustment means as described.

I claim:

1. Vibration damping means for a circular saw, the means including a blade guide holder secured to a support, the holder being generally U-shaped in section and having opposite sides spaced to accommodate the saw, the guide holders having lower ends having a leading opening provided in each side and opposite lower ends having a following opening provided in each side, the openings being spaced radially inwards clear of throats of the teeth and having side walls, each opening accepting a guide plug of a guide plug pair, inner faces of the plugs being spaced oppositely on either side of the saw and disposed at a small clearance from opposite surfaces of the saw, each plug having:

a. a central bore having a pipe thread,

b. a radial slot extending to the central bore from an outer periphery of the plug,

c. a pipe threaded stud adapted to be screwed into the central bore,

so that tightening of the stud expands the plug against the sidewall of the opening so as to provide means of adjusting the small clearance.

2. Vibration damping means as claimed in claim 1 in which i. the leading and following openings are diametrically opposite, and ii. the holder has a third pair of oppositely disposed openings, the third pair of openings being disposed at between 65 and from the leading opening towards the following opening, the third pair of openings accepting a similar plug pair. 3. Vibration damping means as claimed in claim 1 in which i. the radial slot of the guide plug extends beyond the central bore. 4. Vibration damping means as claimed in claim 1 in which i. the sidewalls of the openings in the holder are cylindrical, and ii. the guide plugs have complementary cylindrical sidewalls. 5. Vibration damping means as claimed in claim 4 in which i. the guide plug has a diameter essentially equal to the diameter of the opening. 6. Vibration damping means as claimed in claim 3 in which j. the radial slot of the guide extends a total length of about three-quarters of the diameter of the guide plug. 7. Vibration damping means as claimed in claim 1 in which i. the openings are concentric about an axis of the saw.

8. Vibration damping means as claimed in claim 1 in which 1. radial peripheries of the plugs are positioned so as to be adjacent throats of teeth of the saw. 9. Vibration damping means as claimed in claim 2 in which i. the radial slot of the guide plug extends beyond the central bore. 10. Vibration damping means as claimed in claim 2 in which i. the sidewalls of the openings in the holder are cylindrical, and ii. the guide plugs have complementary cylindrical sidewalls. 

1. Vibration damping means for a circular saw, the means including a blade guide holder secured to a support, the holder being generally U-shaped in section and having opposite sides spaced to accommodate the saw, the guide holders having lower ends having a leading opening provided in each side and opposite lower ends having a following opening provided in each side, the openings being spaced radially inwards clear of throats of the teeth and having side walls, each opening accepting a guide plug of a guide plug pair, inner faces of the plugs being spaced oppositely on either side of the saw and disposed at a small clearance from opposite surfaces of the saw, each plug having: a. a central bore having a pipe thread, b. a radial slot extending to the central bore from an outer periphery of the plug, c. a pipe threaded stud adapted to be screwed into the central bore, so that tightening of the stud expands the plug against the sidewall of the opening so as to provide means of adjusting the small clearance.
 2. Vibration damping means as claimed in claim 1 in which i. the leading and following openings are diametrically opposite, and ii. the holder has a third pair of oppositely disposed openings, the third pair of openings being disposed at between 65* and 75* from the leading opening towards the following opening, the third pair of openings accepting a similar plug pair.
 3. Vibration damping means as claimed in claim 1 in which i. the radial slot of the guide plug extends beyond the central bore.
 4. Vibration damping means as claimed in claim 1 in which i. the sidewalls of the openings in the holder are cylindrical, and ii. the guide plugs have complementary cylindrical sidewalls.
 5. Vibration damping means as claimed in claim 4 in which i. the guide plug has a diameter essentially equal to the diameter of the opening.
 6. Vibration damping means as claimed in claim 3 in which j. the radial slot of the guide extends a total length of about three-quarters of the diameter of the guide plug.
 7. Vibration damping means as claimed in claim 1 in which i. the openings are concentric about an axis of the saw.
 8. Vibration damping means as claimed in claim 1 in which
 9. Vibration damping means as claimed in claim 2 in which i. the radial slot of the guide plug extends beyond the central bore.
 10. Vibration damping means as claimed in claim 2 in which i. the sidewalls of the openings in the holder are cylindrical, and ii. the guide plugs have complementary cylindrical sidewalls. 